In the aforesaid application, there is disclosed a drive assembly for rotating a shaft of a belt driven device. The drive assembly includes a hub in the form of an annular body of ferrous metal having a groove in an external periphery thereof. A belt driven pulley is provided in the form of ferrous sheet metal and includes a web portion. A structural connection is defined between the hub and the pulley web portion such that the hub is fixed in abutted relation with the pulley web portion. The hub and the pulley web portion have a bore therethrough defining a single, machined annular surface. The annular surface is constructed and arranged to engage a periphery of the shaft in an interference-fitted manner so as to maintain torque transfer to the shaft in the event of failure of the structural connection. The groove is constructed and arranged to be operatively engaged by a pulling tool for removing the annular surface from engagement with the shaft.
While the pulley made in accordance with the principles of the aforesaid application disclosure is satisfactory, there is always the need to provide a pulley which is more cost effective. One way in which such cost effectiveness can be achieved is to provide a pulley which is lighter while maintaining the same or better performance level.
An object of the present invention is to fulfill the need expressed above. In accordance with the principles of the present invention, this objective is achieved by providing a drive assembly for rotating a shaft of a belt-driven device which comprises a hub in the form of an annular body of ferrous metal having a radially outwardly projecting annular portion, a pulley made of light weight non-ferrous metal, and a connecting ring of ferrous metal. The pulley has a web portion formed with an axially extending annular portion at a radially inward position thereon. The connecting ring is disposed in surrounding relation with the axially extending annular portion and has a connection therewith constructed and arranged to rigidify the connecting ring and the pulley. The hub has a connection with the connecting ring constructed and arranged to rigidify the hub with the pulley through the connecting ring. The web portion includes the annular extension thereof and the hub which has a bore therethrough defining a single machined annular shaft-engaging surface. The shaft-engaging surface is constructed and arranged to engage a periphery of the shaft in an interference-fitted manner so as to maintain torque transfer between the pulley and shaft in the event of the failure of either or both of the connections. The hub and the connecting ring are constructed and arranged with respect to the axially extending annular portion to provide an annular space adjacent the radially outwardly projecting annular portion of the hub of a size to allow a pulling tool to enter the annular space and act upon the radially outwardly projecting annular portion to remove the pulley from the periphery of the shaft.
Another object of the present invention is to provide a combination which includes the above-described drive assembly and a vehicle hydraulic power steering pump having a drive shaft wherein the single machined annular shaft-engaging surface is engaged with the periphery of the shaft in an interferencefitted fashion.
Another object of the present invention is the provision of a cost effective method of making a pulley. In accordance with the principles of the present invention, this objective is achieved by providing a method of making a pulley which comprises the steps of forming a pulley of lightweight non-ferrous metal having a web portion, forming a radially inward portion of said web portion into an axially extending annular portion, mounting a connecting ring of ferrous metal having an annular groove in an interior end surface thereof over the axially extending portion of the web portion so that a free end of the axially extending portion extends adjacent the annular groove, cold-forming the free end to fill the annular groove, welding a hub of ferrous material to the connecting ring, and machining a central axial bore through the web portion including the axially extending portion thereof and the hub.
These and other objects of the present invention will become more apparent during the course of the following detailed description and appended claims.
The invention may best be understood with reference to the accompanying drawings wherein an illustrative embodiment is shown.